Patients undergo total body irradiation twice daily on days -5 and -4. Patients receive anti-thymocyte globulin IV on days -5, -3, -1, 1, 3, and 5 and cyclophosphamide IV on days -3 and -2. CD34-selected PBSCs are reinfused on day 0. Patients receive G-CSF IV daily beginning on day 0 and continuing until blood counts recover.